Understanding energetic particle effects on atmospheric processes

Lead Research Organisation: University of Bath
Department Name: Electronic and Electrical Engineering

Abstract

Our moderate climate makes life on Earth possible. In order to predict how our climate will change in future, it is necessary to understand all of the processes, both natural and man made, which can contribute to climate change. Climate scientists have a fairly good grasp of the anthropogenic factors, but there are gaps in our knowledge about the contribution to climate change from natural variability. One of the major sources of uncertainty is the variability caused by our sun. The brightness of the sun influences Earth's climate directly by heating, and varies mainly on an 11 year timescale. This direct effect is relatively well understood, however there are other indirect effects (which are linked to solar output, but require another physical process in between) which are thought to influence Earth's climate, and are not at all well understood. It is essential that these indirect effects are better understood if we are to accurately account for solar effects in predicting future climate change.

My research will investigate one of the potential indirect effects of solar variability on atmospheric processes, which is the effect of electrical charge on clouds. Charge is created in the atmosphere by ionisation from Galactic Cosmic Rays (GCRs) (highly energetic particles from outside our solar system). When GCRs approach Earth, they are deflected by both the Solar and Earth's magnetic field, which act as a selective energy barrier to GCRs. The sun's magnetic field varies mainly on an 11 year timescale, therefore GCR fluxes, and thus charge in the atmosphere is controlled by solar activity. Due to constant vertical flow of charge in the atmosphere, charge accumulates at the upper and lower boundaries of layer clouds (the very common sort of clouds that you see on an overcast day). The charge sticks to the cloud droplets, which is thought to influence the behaviour of the droplets, such as how they grow and stick together, which can be seen in large scale cloud properties like cloud height. Since such clouds control heating and cooling in the atmosphere, and cover around 40% of the Earth's surface at one time, charge effects on clouds may have implications for climate. My research will investigate the factors that control charge in the atmosphere, determine whether charge plays a role in cloud processes, and ultimately determine whether this is important for climate.

In order to characterise the factors controlling charge in the atmosphere, and the typical charge present inside layer clouds, measurements will be made using a suite of newly developed sensors which have been designed to fly alongside conventional weather balloons. These lightweight, disposable sensors provide a cost effective method of obtaining extra science data above the surface, from weather balloons which are already being launched around the world by global meteorological services. These airborne measurements will be combined with surface measurements of charge and atmospheric electricity at various sites around the world to understand the global response of charge to changes in solar variability. Such measurements are rare and are vital to understand the physical mechanisms responsible for modulating vertical charge flow and therefore coupling between Space Weather and the lower atmosphere.

This topic sits at the intersection of physics and meteorology and presents an opportunity to investigate processes that we are still very much in our infancy of understanding. There is a great deal of exciting and potentially very important fundamental research to be done in this field, which will ultimately help us to understand whether these new processes are relevant to climate.

Planned Impact

The research proposed by this fellowship application is relevant to a number of non-academic beneficiaries:

Policy makers and general public
There is a wide interest from the general public and policy makers in natural sources of climate variability. Suggestions that cosmic rays can provide an unexpectedly large natural influence on climate have been used to refute the need to curb carbon dioxide emissions. In order to challenge such assertions, new quantitative knowledge about the affect of cosmic rays on climate is necessary, which this fellowship aims to address. Once the natural sources of climate variability have been accounted for, both the general public and policy makers will benefit from the improved and more accurate climate modelling that will result.

Commercial
The special science sensors developed as part of this fellowship use novel instrumentation techniques which can extend the usefulness of the pre-established measurement infrastructure of the global radiosonde network. Such an approach is cost effective and can permit measurements to be made in dangerous or remote marine areas. So far, the UK Met Office, British Antarctic Survey, Icelandic Met Office, The Royal Navy and instrument manufacturers Vaisala, Meteomodem and Biral have all expressed interest in the use of novel sensors on radiosondes. Previous commercial work with the UK Met Office resulted in the manufacture and sale of a number of radiosonde sensors for volcanic ash detection. Such interest therefore offers the potential for future spin-out.

Government
The UK Met Office now have an increased interest in Space Weather and its hazards through Space Weather forecasting. A possible destination for the instrumentation used in this Fellowship is in permitting the radiosonde network of the UK Met Office, in which there is long-established substantial investment maintaining the network for routine meteorological observations, to undertake regular measurements of upper atmosphere high energy particles. Interest in the radiosonde sensors has also been expressed by the Icelandic Met Office, for vertical profiling of ash during periods of future volcanic eruptions.

Publications

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Harrison R (2020) Precipitation Modification by Ionization in Physical Review Letters

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Harrison R (2017) Evaluating stratiform cloud base charge remotely in Geophysical Research Letters

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Harrison R (2018) Fair weather criteria for atmospheric electricity measurements in Journal of Atmospheric and Solar-Terrestrial Physics

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Harrison R (2018) Saharan dust plume charging observed over the UK in Environmental Research Letters

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Harrison R (2022) Ionic Charge Emission Into Fog From a Remotely Piloted Aircraft in Geophysical Research Letters

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Harrison R (2019) Shear-induced electrical changes in the base of thin layer-cloud in Quarterly Journal of the Royal Meteorological Society

 
Description This fellowship has successfully produced a number of outcomes related to understanding the effect of energetic particles on atmospheric processes - specifically the effect of atmospheric electricity and charge on cloud processes. Firstly it has produced two unique new datasets of atmospheric electric field measurements, located in high latitude regions in the Arctic and Antarctic, which are central to understanding the role of energetic particles on atmospheric electricity (and therefore clouds). These are summarised in a recent publication (https://doi.org/10.3389/feart.2020.614639).

It has also produced more than 30 specially instrumented balloon flights through stratiform layer clouds, measuring charge and droplet properties. This data demonstrated robustly that, on average, the electrical charge present in stratiform layer clouds agrees with that predicted by theory (https://doi.org/10.1002/qj.2858), but with considerable variability in the charge on an individual cloud-to-cloud basis. This unique dataset also demonstrates for the first time that asymmetry exists between the cloud top and cloud base charge (due dynamical reasons), which results in more pronounced effects of charge on droplets at cloud top than cloud base. Further advances made during the fellowship include the development of a new technique to detect charge in cloud bases remotely (rather than in-situ with balloons) (https://doi.org/10.1002/2017GL073128) which allows long term studies of charged particle effects on clouds to be made more straightforwardly and robustly. This technique has been used to examine the role of clouds in Earth's atmospheric electrical system and demonstrated that they are of fundamental importance to the Global Electric Circuit (https://doi.org/10.1098/rspa.2019.0758). Collaborations developed with international colleagues is also leading to modelling work to understand the climatic effects of charge effects on clouds with publications expected on this in the near future.

As well as advances in measurement techniques, there have also been several technological developments related to the project, including the development of a miniature electric field sensor for use on balloon and unmanned aircraft platforms (NERC PhD award ref: 1943543). Also, balloon borne sensors which measure the vertical profile of charge production (ionisation) in the atmosphere have now been flown in at least 5 different countries worldwide (e.g. https://doi.org/10.1016/j.jastp.2016.10.003), and the technology is now being produced commercially by a world leading instrument manufacturer. This will enable many more measurements to be made to better characterise the variability in ionisation rates across the world in future years. Undergraduate student projects have also been run to measure ionisation at the surface using a new sensor, and to understand the influence of local meteorological influences on the measurements. This fellowship has also succeeded in flying a number of bespoke meteorological sensors (including charge and cloud droplet sensors) on small unmanned aerial vehicles (UAVs). Flights have taken place in clear air conditions, and through low level cloud (up to 2km) at specially designated flying sites in 5 countries so far. This provides a reliable and cost effective way to sample charge and droplet properties in clouds, and also allows the ambient cloud environment to be perturbed by deliberately releasing charge into clouds to study the effects on the cloud droplet behaviour (https://doi.org/10.1175/JTECH-D-20-0092.1).
Exploitation Route The new datasets generated by this fellowship (e.g. electric field measurements in the Arctic and Antarctica) are already being used by other researchers to study global atmospheric electricity and space weather. The measurements of cloud charge are also being used internationally by the modelling community to inform modelling studies on the effect of charge on cloud processes, and therefore potentially on climate. Finally, the instrumentation developed has been described in the international scientific literature, and to meteorological instrument manufacturers. Research proposals are already intending to use the equipment.
Sectors Environment

 
Description International Exchanges 2017 Cost Share
Amount £10,000 (GBP)
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 03/2018 
End 10/2019
 
Description United Arab Emirates Rain Enhancement Programme
Amount $1,500,000 (USD)
Funding ID Electrical aspects of rain generation 
Organisation United Arab Emirates Government 
Sector Public
Country United Arab Emirates
Start 03/2017 
End 10/2019
 
Title Cloud electricity measurements over Halley, Antarctica 
Description Meteorological radiosondes, measuring standard thermodynamic quantities but also modified to measure electrical properties of extensive layer clouds, were released from the Halley base of the British Antarctic Survey on 20th and 21st of Feb 2015. The measurements obtained from these two soundings are provided here. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
Impact None as yet 
URL https://researchdata.reading.ac.uk/id/eprint/420
 
Title Dataset for 'Consistent dust electrification from Arabian Gulf sea breezes' 
Description This dataset contains atmospheric electric field, visibility and ceilometer data contained within the paper 'Consistent dust electrification from Arabian Gulf sea breezes' by K.A. Nicoll, R.G. Harrison, G.M. Marlton and M.W. Airey, submitted to Environmental Research Letters (2020). The measurements were obtained at Al Ain airport (24°15' N, 55°37' E), United Arab Emirates (UAE) in the year 2018. The data has been used within this paper to study the electrification of dust lofted by sea breeze events. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact None as yet. 
URL https://researchdata.reading.ac.uk/id/eprint/246
 
Title GLOCAEM PG database 
Description The GLOCAEM database contains the first real time accessible atmospheric electric field data from a number of sites world wide (20 so far). It is hosted by CEDA and contains 1 second and 1 minute average daily files of electric field and meteorological measurements. The data is freely accessible to other researchers. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact The electric field data from the GloCAEM dataset has been used by researchers worldwide, and has led to at least 4 peer reviewed publications from researchers unaffiliated with the GloCAEM project. These include: Wu, J., Zou, Z., Li, Y., & Xie, F. (2024). The possibility of rainfall nowcasting using atmospheric electric field. Atmospheric Research, 298, 107118. Velazquez, Y. R., Nicora, M. G., Galligani, et al. (2022). The 2020 Patagonian solar eclipse from the point of view of the atmospheric electric field. Papers in physics, 14, 140008-140008. Velazquez, Y. R., Nicora, M. G., Galligani, V. S., Wolfram, E. A., Salio, P. V., & D'Elia, R. L. (2024). Exploring the global thunderstorm influence on the fair weather electric field in Buenos Aires. Atmospheric Research, 299, 107182. Li, L., Chen, T., Shen, C., Ti, S., Wang, S., Cai, C., ... & Luo, J. (2023). Near-surface atmospheric electric field changes through magnetic clouds via coronal mass ejections. Geoscience Letters, 10(1), 45. 
URL https://catalogue.ceda.ac.uk/uuid/bffd0262439a4ecb8fadf0134c4a4a41
 
Title Observed variability in charging of stratiform cloud edges 
Description This dataset describes charge and meteorological data measured from radiosondes as described in the paper: Observed variability in charging of stratiform cloud edges", by K.A. Nicoll and R.G. Harrison. 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
Impact None as yet 
URL http://researchdata.reading.ac.uk/id/eprint/38
 
Title On the detection of pressure perturbations during the March 2015 solar eclipse - supplementary data 
Description A collection of data used in the paper: On the detection of pressure perturbations during the March 2015 solar eclipse. Includes surface measurement data from the University of Reading Atmospheric Observatory and data from the University of Reading research launches from the Met Office Observatory. 
Type Of Material Database/Collection of data 
Year Produced 2015 
Provided To Others? Yes  
Impact None as yet. 
URL http://researchdata.reading.ac.uk/id/eprint/5
 
Title Supplementary data for "First observations of gaseous volcanic plume electrification: a new source of charge for volcanic lightning" 
Description This dataset contains the processed radiosonde and additional surface VOLCLAB sensor data for a measurement campaign at Stromboli volcano during 28th September to 4th October 2017. Full details are given in the paper titled "First observations of gaseous volcanic plume electrification: a new source of charge for volcanic lightning", submitted to Nature Geoscience. The data for figures 1,3 and 4 are provided here. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact None as yet. 
URL http://researchdata.reading.ac.uk/id/eprint/154
 
Title Supplementary data for Note: A self-calibrating wide range balloon electrometer 
Description This dataset contains the radiosonde and additional sensor data for an adapted radiosonde launched on the 22nd September 2017 from Pallas at 0915 UT. The file contains standard meteorological data and the additional sensor channels that were used in the analysis shown in the Review of Scientific Instruments note: A self-calibrating wide range balloon electrometer by R. Giles Harrison, Graeme J. Marlton, Keri A. Nicoll, Martin W. Airey, Paul D. Williams. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact None as yet. 
URL http://researchdata.reading.ac.uk/id/eprint/127
 
Description COST action on Atmospheric Electricity CA15211 
Organisation Democritus University of Thrace
Country Greece 
Sector Academic/University 
PI Contribution I am one of the UK Management Committee representatives for this COST action network.
Collaborator Contribution This is an international network with over 40 countries involved.
Impact Savoska,S., P. Fernandez-Arroyabe, M. Cifra, K. Kourtidis, E. Rozanov, K.A. Nicoll, S. Dragovic, L.M. Mir. (2020) Ontology of atmospheric electricity coupling with biological systems, International Journal of Biometeorology, 65, 31-44, https://doi.org/10.1007/s00484-020-02051-3, 2021 Hunting E., J. Matthews, P. Fernández de Arróyabe Hernáez, S.J. England, K. Kourtidis, K. Koh, K.A. Nicoll et al., Challenges in coupling atmospheric electricity with biological systems, International Journal of Biometeorology, https://doi.org/10.1007/s00484-020-01960-7, 2020
Start Year 2016
 
Description Appearance on BBC1 "The One Show" 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact I was interviewed on camera as part of a special programme for "The One Show" as an expert on the atmospheric electric field. Up to 5 million viewers watch the programme every week.
Year(s) Of Engagement Activity 2020
 
Description Bath Science Cafe talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact In February 2016 I was invited to give a talk at the Bath Science Cafe in the Raven pub. This was received with great enthusiasm with lots of questioning from the general public afterwards.
Year(s) Of Engagement Activity 2016
 
Description Creation of public website 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact A public website was created to highlight the GloCAEM database to the general public, as well as to explain about the atmospheric electric field and how to measure it. I have since been contacted by several members of the public requesting advice about their own atmospheric electric field sensors.
Year(s) Of Engagement Activity 2018
URL https://glocaem.wordpress.com/
 
Description Feature length segment on BBC radio4 (The curious cases of Rutherford and Fry) 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact I recorded a feature length segment for BBC radio 4 as part of their programme "The curious cases of Rutherford and Fry". For this I provided advice, interviews on radio as well as perfomed a balloon launch experiment which was recorded for radio. Radio 4 have received feedback on this from several interested members of the public.
Year(s) Of Engagement Activity 2017
URL http://www.bbc.co.uk/programmes/w3cswd1s
 
Description Interview with Science magazine 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interviewed by Science magazine about my research paper on volcanic charge generation processes. They wrote an article based on this which featured in their magazine.
Year(s) Of Engagement Activity 2019
URL https://www.sciencemag.org/news/2019/03/volcanic-lightning-may-be-partially-fed-earth-s-natural-radi...
 
Description Interview with The New York Times 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interviewed by The New York Times about my research paper on volcanic charge generation processes. They wrote an article based on this which featured in their newspaper.
Year(s) Of Engagement Activity 2019
URL https://www.nytimes.com/2019/03/29/science/volcanoes-lightning-radon-gas.html
 
Description Physics Review article 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact I have written an article on atmospheric electricity for Physics Review. This is a magazine which supports the studies of physics students, who are studying for A-levels, AS-levels, GNVQ, Irish or Scottish Highers, or Scottish CSYS. The article will be published in the March 2016 edition of the magazine therefore as yet there has been no opportunity for impact.
Year(s) Of Engagement Activity 2016
 
Description Press interview for EOS article "Studying Earth's double electrical heartbeat" 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact I provided an interview about the global electric circuit and my NERC project GloCAEM to a journalist who was writing an article for EOS, the science magazine of the American Geophysical Union. The article prompted enquires about the GloCAEM project and an offer of addtional datasets for the project. The article was also picked up by a variety of science websites including: https://science.thewire.in/the-sciences/earth-global-electrical-circuit-carnegie-curve-ionosphere/.
Year(s) Of Engagement Activity 2020
URL https://eos.org/features/studying-earths-double-electrical-heartbeat
 
Description Public lecture RMetS Scottish centre 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Public lecture to the Scottish Centre of the Royal Meteorological Society on "Electricity in the atmosphere: airborne measurements from balloons and drones".
Year(s) Of Engagement Activity 2016
URL https://www.rmets.org/events/measuring-electricity-atmosphere-balloons-and-drones
 
Description Public lecture RMetS south east centre 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Public lecture at the South East centre of the Royal Meteorological Society entitled "Atmospheric electricity research at Halley, Antarctica". I have since had several queries from interested members of the general public on atmospheric electricity and instrumentation.
Year(s) Of Engagement Activity 2016
URL https://www.rmets.org/events/atmospheric-electricity-research-halley-antarctica
 
Description Public lecture for the Institution of Engineering and Technology (IET) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact 50 members of the general public (including all ages from school children to retired people) attended a public lecture which I gave for the IET in December 2017. Feedback from the members of the audience was excellent, with many saying it was the best talk they'd heard in years. I have since had several emails from members of the public asking for more information about the subject.
Year(s) Of Engagement Activity 2017
URL https://localevents.theiet.org/4efac2
 
Description Public talk to Scottish Centre of the Royal Meteorological Society 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact I gave a public talk to Scottish Centre of the Royal Meteorological Society in Dec 2023 on the electrification of extensive layer clouds. This was very well received by the audience, many of whom asked for further information afterwards and I was invited to give an additional talk at a later date.
Year(s) Of Engagement Activity 2023
URL https://www.rmets.org/event/electricity-extensive-layer-clouds
 
Description Radio interview for BBC radio Berkshire 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact I performed an interview on BBC Radio Berkshire in reponse to media queries about new cloud charging research which I am involved with.
Year(s) Of Engagement Activity 2017